This is a broad program of research on the genetic epidemiology of psychiatric disorders and alcoholism. The field of genetic epidemiology is concerned with the etiology, distribution, prognosis, and control of disease in families, particularly heritable diseases of biomedical significance. The research has three long-term goals: (1) To describe and test alternative classification schemes for psychiatric disorders by means of follow-up and family studies, with emphasis on identifying homogeneous clinical subgroups; (2) To evaluate the mode of inheritance of psychiatric disorders and associated biosocial risk factors using segregation and linkage analysis; (3) To evaluate gene-environment interaction in cross-fostering studies of adoptees and path analysis of multiple classes of relatives varying in genetic and social relationship. This work is being carried out in three long-term projects in the United States and Sweden. The award will facilitate the activities of the investigator in research and research training.